Katja´s Bed & Breakfast is a place I can´t recommend enough. Clean, comfortable and well-located. Gianluca, the owner, is more than helpful and makes his guests feel at home at all times. I found this place just perfect to get closer to the feel of genuine roman life, as it is in fact an apartment (beautifuly decorated, I must add) in a quite calm area of the city, though the Vatican is just up the street.
Room is small, but very comfortable. Bathroom is shared by the two only rooms and is always kept very clean, with soap, hair dryer and towels available.
Breakfast is copious! Tea, coffee, juice, bread, jam, butter, nutella, fruit and some fresh cold dishes of cheese, salami and vegetables. You can even skip lunch!
It is located right by the Vatican, reachable by several bus lines. It is a walkable distance from the tourist hot spots across the Tiber, and it feels great to start the day walking right through Saint Peter´s Square! There are some fine restaurants just around the corner. Trastevere, packed with bars and more restaurants, is just a few minutes by bus.
In short, a highly recommend place to stay!